Friction clutch



Dec. 3l, 1929. r e. A. scHE-rTLER 1,741,438

FRICTION CLUTCH Filed Aug. l0. 1925 a8 4o se a 42' sa 34 l' 8 u /la IHVEHTDY' Patented Dec. 31, 1929 UNITED STATES PATENT OFFICE GUSTAV ADOLF SCHETTL-ER, OF BRAMLEY, ENGLAND', ASSIGNOR T0 THE TURNER TANNING MACHINERY COMPANY, OF PORTLAND, MAINE, A CORPORATION OF MAINE FRICTION CLUTCH Application filed August 10, 1925, Serial No. 49,311, and in Great Britain May 2, 1925.

connect a driving and a. driven member. ItV

is an object of the invention to provide an improved clutch of this type having a rugged 1- u ing the clutch in engaged or operative posiconstruction which will be especially suitable for heavy vduty machines such as, for exam-y ple, certain machinesused in the tanning industry. I

In theuse of prior'constructions of this l character 'considerable objectionable friction has been encountered indeforming the fric-- tion ring to a grippingv position, because a radially movable member with a wedgeshaped end has beenused to slideon a correspondingly wedge-shapedA abutment' on the friction ring and so wedge the ring into clutch engaging position. This friction has a radial component which tends to force the ring out of co-axial relation'with the member it is arranged to grip andv thereby causes an excessive and uneven wear of these parts.

In order to overcome lthe'above mentioned objections, a feature of the invention consists in interposing an antifriction toggle link between the friction ring, which is preferably resilient, and the radially movable member that operates it. In this manner, unnecessary friction in this portion of the controlling mechanism of the clutch is eliminated so that the mechanism is made to operate easier. The illustrated toggle .link is so arranged that, when the clutch is in engaged or operative position, the thrust of the link against the friction ring is, or'may. be adjustedto be, tangential to the ring, without any .radial thrust to produce uneven wear. 'This adjustment is also such as to maintain the clutch parts in engaged position and lock them against disengagement. L

. Other features of the invention will be apl Aparentfrom the following description when of thearrows and showing the clutch in engaged -or operative position gf Fig. 2 is a cross section' taken along the line 2-2 in Fig. 3, looking in the direction of the arrows and showing the clutch in disengaged or inoperative position;

Fig. 3 is a side elevation, partly in section, showing the clutcn in inoperative position;

Fig. 4 is a view similar to Fig. 3 but showis arranged as a means for connecting and" disconnecting a shaft 10 with a gear 12, either of which may be used as the driving member. Mounted on the shaft is a clutch boxi14 which is secured thereto by set screws 16. Vithin the clutch box is 'a contractible friction ring 18 shown in detail in Fig. 5. Preferably and as illustrated, this ring consists of two convolutions 20 and 22 separated by a continuous groove 24 of such a width as to permit contraction of each Yconvolution in order that the inner vsurface of the ring may firmly grip the outer surface of a sleeve attached to or integral with the gear 12 and thereby drive the mechanism which is controlled by the 'clutch without slipping, as will be more fully described later. The continuous groove 24 extends longitudinally from one end of the ring to its middle, then circumferentially for approximately three-quarters of the way around the ring` and then longitudinally to the opposite4 end of the ring. Near the free ends of the convolutions are projecting lugs or abutments 26 and 28A, which serve to receive the pressure for contracting the ring, as will later be explained.

For controlling the clutch, a collar 30 is slidingly mounted upon the shaft 10. This collar is providedA with a circumferential groove 32by which it may be slid along the shaft by the usual operating yoke (not shown) having rolls which run in the groove. The collar 32 is provided with a pivot screw 34 upon which a link 36 is mounted. This link 36 is connected by a pivot 38 to one arm 40 of a bell crank lever. The other arm 42 of the bell crank lever eXtends within the clutch boX, the bell crank lever 40, 42 being pivotally mounted on the box at 44. It will be seen that, by moving the collar 30 longitudinally of the shaft, the outer end of the arm 42 of the bell crank lever .moved in a substantially radial direction either toward or from the shaft so as respectively to contract or to permit expansion of the friction ring -1-8. The varm 42 ofthe bell crank lever is thus a radially movable member for operating the friction ring and deforming it and, in the illustratedconstruction, specifically, for contracting it.

An anti-friction toggle link 46, preferably duinb-bell shaped, is interposed between the a-rm 42 of the bell crank lever-and thelug 26 of the friction ring, being arranged tooperate in a plane substantially parallel to the pivot 44. This toggle link is provided with spherical ends which are seated, respectively, in spherical recesses in the bell crank arm 42 and lug 26. The toggle link is thus held in `position without any additional retaining means. When the farm 42 is in the Vp ositionshown in Fig. 2, the friction ring is open but ywhen the arm 42 is moved radially so that the toggle link 46 assumes a .position tangential to the ring 18 as shown in Fig. 1, the ring is contracted and engages a lsleeve 48 which may be l.integral with the lgear 12 yor securely attached thereto. In order -to produce the proper friction on the sleeve 48, an adjusting screw 50 passes through the clutch box 14 and is set up against the lug` 28 on the friction ring until the desired friction is obtained when the toggle link is brought into a position tangential to the friction ring, this being the engaged or operative position of the clutch. The adjusting screw is then locked in position by the check nut 52. If the parts should wear, the adjusting screw 50 provides a ready means for taking up such wear.

It will be noted that, with the toggle link 46 in the tangential position shown in Fig. 1, all radial thrust is removed from the friction ring and a possible source of wear eliminated. It will be further noted that the end of the bell crank arm 42 is supported on the inner surface 54 of the clutch box 14, thereby eliminating side strain on the pivot 44 to which the toggle link 46, when in its tangential -position, is parallel. Furthermore, when the toggle link is in tangential position, the thrust of the link on the bell crank arm 42 is perpendicular to the surface 54 of the clutch box so'there is no tendency to move the bell crank arm 42. Accordingly, the clutch is lockedin lclosed position `and will remain so without any strain being exerted on the parts to maintain it in that position, until the collar 80 is operated.

lt will also be noted that in applicants construction, even if it is necessary to make the lever 4.0 .of considerable Weight in .order to give it strength in a heavy duty machine, it will be held in position against centrifugal force by the link 36 because the collar 80, to which the link is connected, will be held by the usual yoke through the engagement of its rollers with-the groove 32 in the collar. The

position of the yoke (and the ,corresponding position of the collar and the clutch operating member) will be controlled by the operator by 'means of a foot treadle or similar device. In this manner the liability lof the clutch to chatter due to the action-of centrifugal v*force in causing partial engagement is claim as new and desire to secure by Letters Patent of the United States is:

1. In a vclutch mechanism, a friction ring ofmore thanone turn, a pivot fixed .relatively to the ring, a member mounted on said pivot and radially movable toward and away from the longitudinal axis of the ring vfor deforming the turns of the ring, and a toggle vlink jnterposed between the ring and said mem- 2. In a clutch mechanism, a friction ring., a pivot, a lever mounted on the pivot, a toggle link interposed between the lever and ring, and an abutment for the lever opposite the toggle link whereby the pivot is relieved of side strain as the lever is moved.

3. In a clutch mechanism, a resilient fric a pivot shaftfor said member, sockets in the ring and said member, and a toggle link interposed between the ring and said member and arranged to operate in a plane substantially parallel to said pivot shaft, the ends of the link being held in said sockets without any additional retaining means.

4. In a clutch mechanism, a friction ring, a pivoted lever for deforining the ring by acting on one end thereof, a toggle link interposed between the ring and said member, and means for adjusting the position of the opposite end of the ring whereby the toggle link may be positioned, when the clutch is in full engagement, tangentiall-y to the ring. i

5. In a clutch mechanism, a shaft, a. friction ring, a member for ldeforming the ring, a pivotal support for said member, a sliding Colla-r 0n the shaft, connections between the collar and ksaid member for operating the member, and a dumb-bell shaped .toggle link connected to said .member and engaging said tion ring, a member for contracting the ring,

ring, said toggle link being arranged to operate in a plane substantially parallel to said pivotal support.

6. In a clutch mechanism, a clutch box, a resilient friction ring within the box, a lever pivoted on the box for contracting the ring, Y 

